1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_dct4_init_f32.c
4 * Description: Initialization function of DCT-4 & IDCT4 F32
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/transform_functions.h"
30 #include "arm_common_tables.h"
31
32 /**
33 * @defgroup DCT4F32 DCT4 F32
34 */
35
36 /**
37 @ingroup DCT4_IDCT4
38 */
39
40 /**
41 @addtogroup DCT4F32
42 @{
43 */
44
45 /**
46 @brief Initialization function for the floating-point DCT4/IDCT4.
47 @deprecated Do not use this function. It is using a deprecated version of the RFFT.
48 @param[in,out] S points to an instance of floating-point DCT4/IDCT4 structure
49 @param[in] S_RFFT points to an instance of floating-point RFFT/RIFFT structure
50 @param[in] S_CFFT points to an instance of floating-point CFFT/CIFFT structure
51 @param[in] N length of the DCT4
52 @param[in] Nby2 half of the length of the DCT4
53 @param[in] normalize normalizing factor.
54 @return execution status
55 - \ref ARM_MATH_SUCCESS : Operation successful
56 - \ref ARM_MATH_ARGUMENT_ERROR : <code>N</code> is not a supported transform length
57
58 @par Normalizing factor
59 The normalizing factor is <code>sqrt(2/N)</code>, which depends on the size of transform <code>N</code>.
60 Floating-point normalizing factors are mentioned in the table below for different DCT sizes:
61
62
63 | DCT Size | Normalizing factor value |
64 | --------: | ------------------------: |
65 | 2048 | 0.03125 |
66 | 512 | 0.0625 |
67 | 128 | 0.125 |
68
69 */
70
arm_dct4_init_f32(arm_dct4_instance_f32 * S,arm_rfft_instance_f32 * S_RFFT,arm_cfft_radix4_instance_f32 * S_CFFT,uint16_t N,uint16_t Nby2,float32_t normalize)71 arm_status arm_dct4_init_f32(
72 arm_dct4_instance_f32 * S,
73 arm_rfft_instance_f32 * S_RFFT,
74 arm_cfft_radix4_instance_f32 * S_CFFT,
75 uint16_t N,
76 uint16_t Nby2,
77 float32_t normalize)
78 {
79 /* Initialize the default arm status */
80 arm_status status = ARM_MATH_SUCCESS;
81
82
83 /* Initialize the DCT4 length */
84 S->N = N;
85
86 /* Initialize the half of DCT4 length */
87 S->Nby2 = Nby2;
88
89 /* Initialize the DCT4 Normalizing factor */
90 S->normalize = normalize;
91
92 /* Initialize Real FFT Instance */
93 S->pRfft = S_RFFT;
94
95 /* Initialize Complex FFT Instance */
96 S->pCfft = S_CFFT;
97
98 switch (N)
99 {
100 /* Initialize the table modifier values */
101 case 8192U:
102 S->pTwiddle = Weights_8192;
103 S->pCosFactor = cos_factors_8192;
104 break;
105
106 case 2048U:
107 S->pTwiddle = Weights_2048;
108 S->pCosFactor = cos_factors_2048;
109 break;
110
111 case 512U:
112 S->pTwiddle = Weights_512;
113 S->pCosFactor = cos_factors_512;
114 break;
115
116 case 128U:
117 S->pTwiddle = Weights_128;
118 S->pCosFactor = cos_factors_128;
119 break;
120 default:
121 status = ARM_MATH_ARGUMENT_ERROR;
122 }
123
124 /* Initialize the RFFT/RIFFT Function */
125 arm_rfft_init_f32(S->pRfft, S->pCfft, S->N, 0U, 1U);
126
127 /* return the status of DCT4 Init function */
128 return (status);
129 }
130
131 /**
132 @} end of DCT4F32 group
133 */
134
